This invention relates to a device for indicating the position of a rotary shaft and more particularly to an indicator which may be operably controlled at both its initial and closing positions.
The present invention is particularly applicable to both fluid and flow systems in which it is desirable to monitor the condition of rotary valves, that is, whether they are open or closed, and to also control the opening or closing of successive valves in the flow line as a function of the condition of the preceeding valves. Most typically, electrical switches are mechanically opened or closed in response to the state of the rotary valve. The problem becomes aggravated where a particular gate or slide valve is to be monitored as being opened when in fact, it may still be closed. Some means is necessary to properly determine when the valve is "opened" and when the valve is "closed". With the use of the present switch arrangement, and cam operated screws, the initial and closed conditions of a valve are correctly simulated with such a mechanism regardless of the condition of other valves having a comparable position. That is, several may open at different times and several may close at different times even though they are all considered to be in an "open" or "closed" position.